Cytocompatibility assessment of chemical surface treatments for phosphate glass to improve adhesion between glass and polyester

Fully resorbable phosphate glass fiber reinforced polymer composites have shown real potential for replacing some of the existing metallic bone fracture fixation devices. However, some of these composites have not provided suitable mechanical strength profiles over the required healing period for bone. Typically, it has been seen that these composites can lose up to 50% or more of their strength within the first week of degradation. Functionalizing the glass surface to promote polymer adhesion or to introduce hydrophobicity at the glass surface could potentially introduce control over the mechanical properties of the composite and their retention. In this study eight chemical agents namely, Glycerol 2-phosphate disodium salt; 3-phosphonopropionic acid; 3-aminopropyltriethoxy silane; etidronic acid; hexamethylene diisocyanate; sorbitol/sodium ended PLA oligomers and amino phosphonic acid, were selected to functionalise the bulk phosphate glass surface. Selected chemical agents had one functional group (-OH or O C N) to react with the glass and another functionality (either -OH, NH2, or Na) to react with the polymer matrix and/or produce hydrophobicity at the fiber surface. Bulk phosphate glass surface-treated with the above agents were assessed for the cytotoxicity of degradation products cell-material interaction in short- and long-term direct cytocompatibility studies. Results obtained from these cytocompatibility studies (using human osteosarcoma (MG63) and primary human osteoblast cell lines) revealed no cytotoxicity from the degradation products and a response comparable to controls in terms of cell functions (attachment, viability, metabolic activity, proliferation, and differentiation) and morphology.

Mutational dynamics of aroid chloroplast genomes

A characteristic feature of eukaryote and prokaryote genomes is the co-occurrence of nucleotide substitution and insertion/deletion (indel) mutations. Although similar observations have also been made for chloroplast DNA, genome-wide associations have not been reported. We determined the chloroplast genome sequences for two morphotypes of taro (Colocasia esculenta; family Araceae) and compared these with four publicly available aroid chloroplast genomes. Here, we report the extent of genome-wide association between direct and inverted repeats, indels, and substitutions in these aroid chloroplast genomes. We suggest that alternative but not mutually exclusive hypotheses explain the mutational dynamics of chloroplast genome evolution.

Heavy Metals and Major Ionic Pollution Assessment in Waters of Midstream of the River Karatoa in Bangladesh

In a quantitative assessment of water collected from the midstream of Karatoa river in Bangladesh, 31 water samples were analyzed to assess heavy metals, major ionic constituents and suitability parameters for irrigation usage. The electrical conductivity of all collected samples were within the range of 450 to 1653 ?S cm-1 indicating medium to high salinity. Total dissolved solids ranged from 247 to 789 mg L-1 and the samples were rated as fresh water (<1000 mg L-1). The anion chemistry in the Karatoa river water was dominated by HCO3- and Cl-, which contributed 66 and 31%, respectively of the total anionic mass balance. On the other hand, the cation chemistry indicated that 8 samples showed dominance sequence as Ca > Mg > Na > K, 8 samples as Ca > K > Na > Mg, 7 samples as Ca > Mg > K > Na, 6 samples as Ca > Na > K > Mg and only 2 samples as Ca > K > Mg > Na. Among the studied heavy metals (Fe, Mn, Cu, Zn, Pb, Cr and Ni), the most dominant metal was Fe and Mn. The concentration of Mn in 13 water samples exceeded the surface water quality standard (0.10 mg L-1) indicating Mn toxicity. Considering hardness, 6 water samples were graded as moderately hard while the rest 25 samples were graded as hard. As regards to permeability index, 65% of the water samples collected from the midstream of Karatoa river belongs to the unsuitable category.DOI: http://dx.doi.org/10.3329/jesnr.v5i2.14806 J. Environ. Sci. & Natural Resources, 5(2): 149-160 2012

Mycobacterium fortuitum skin infection as a complication of anabolic steroids: a rare case report

Mycobacterium fortuitum is a rare cause of recurrent skin abscesses in an immunocompetent person. We report the case of a 37-year-old man presenting with multiple recurrent non-healing skin abscesses. Culture of the abscess wall yielded growth of M fortuitum. In our case, we highlight the association of anabolic steroids with non-tuberculous mycobacterial skin abscesses that fail to resolve despite repeated drainage.

Fluoroscopically guided balloon dilatation for the treatment of achalasia: long-term outcomes

To report the immediate and long-term outcomes following the fluoroscopically guided balloon dilatations performed in our department for the treatment of achalasia. We reviewed retrospectively all patients that underwent a fluoroscopically guided balloon dilatation because of achalasia in our department between April 2007 and September 2010. The follow-up was performed by interviews and/or investigation of the patient's medical and imaging records. The primary endpoints of the study were technical success, clinical success, major complication rates, and repeat dilatation rates because of recurrence of clinical symptomatology. Secondary endpoints were the rate of minor complications and the dilatation-free interval. Various parameters that could affect the clinical outcome were also analyzed. Thirty-nine consecutive patients (20 female) with a mean age 44 ± 17 years underwent 69 dilatations, while 10/39 (25.6%) patients had a history of a previous laparoscopic myotomy. The most common symptom was dysphagia (64/69, 92.7%), while regurgitation and/or retrosternal pain were present in 12/39 (30.7%) and 9/39 (23%) of the cases, respectively. Technical success was achieved in 98.5% (68/69). There were no procedure-related major complications. The mean balloon diameter used was 30 ± 3.9 mm, and the mean period of follow-up was 27.7 ± 16.0 months. Excellent or good initial responses were noted in 54/66 cases (81.8%). A repeated dilatation to deal with recurrence of symptoms was performed in 69.4% of the cases (25/36). In the majority of the cases, two dilatations were needed in order to achieve long-term relief from symptoms. A dilatation-free interval of 4 years was observed in 26.4%. Clinical success was achieved in 30/36 patients (83.3%). Subgroup analysis did not detect significantly different recurrence rates in patients with and without previous laparoscopic myotomy (50% vs. 69% respectively), those of young age (75% < 21 years vs. 68.8% > 21 years), and male gender (71.4% male vs. 55.0% females). The high redilatation rate was attributed to the utilization of smaller balloons by less experienced operators. Fluoroscopically guided balloon dilatation is a safe and effective method for the treatment of achalasia. Young age and prior Heller's laparoscopic myotomy were not associated with increased rates of recurrence rate or clinical failure.

Efficient analysis of mode profiles in elliptical microcavity using dynamic-thermal electron-quantum medium FDTD method

The dynamic-thermal electron-quantum medium finite-difference time-domain (DTEQM-FDTD) method is used for efficient analysis of mode profile in elliptical microcavity. The resonance peak of the elliptical microcavity is studied by varying the length ratio. It is observed that at some length ratios, cavity mode is excited instead of whispering gallery mode. This depicts that mode profiles are length ratio dependent. Through the implementation of the DTEQM-FDTD on graphic processing unit (GPU), the simulation time is reduced by 300 times as compared to the CPU. This leads to an efficient optimization approach to design microcavity lasers for wide range of applications in photonic integrated circuits.

Abstract P6-09-09: Perceptions of marginalization in those affected by advanced breast cancer

Those living with metastatic breast cancer have distinct and often unmet needs, even compared to others with breast cancer. To help address these needs, the Cancer Support Community has provided for the past five years, Frankly Speaking About Cancer: Advanced Breast Cancer, a comprehensive educational program developed for those with metastatic breast cancer and their loved ones. The program's clinically facilitated evidence-based education workshops have reached 2,690 attendees since the program began in 2006. The workshop provides valuable information about current treatments, clinical trials, side-effect management, and social and emotional challenges of an advanced breast cancer diagnosis. In the present analysis, data across years were merged to investigate the psychosocial and educational needs of those affected by metastatic breast cancer and their perceptions about feeling marginalized.

1,827 workshop attendees nationwide (68% response rate) have responded to survey questions about experiences with advanced breast cancer since the program's inception. In addition to evaluating the workshop and reporting their cancer history, attendees have provided their perceptions of the needs of those with advanced breast cancer, feelings of marginalization, and their own experiences seeking information and support.

64.9% of respondents had been diagnosed with breast cancer; the remainder (35.1%) served in a caregiving capacity. Most respondents (78.5%) were Caucasian, and the mean age was 56 years. Among those with advanced breast cancer, most (66.9%) received the diagnosis at least two years ago. In addition, 75.1% rated themselves in “very good” or “good” health, and 59.6% currently participated in support groups. There was no difference in current support group participation by time since diagnosis.

Of all respondents, the majority (61.2%) endorsed that people with metastatic breast cancer have unique emotional, physical, and informational needs that are often unmet. This percentage remained unchanged across the five years of the program. Furthermore, 31.7% of all respondents endorsed that people with metastatic breast cancer are sometimes stigmatized by others with non-metastatic breast cancer. Among advanced breast cancer patients, those who believed that people with advanced breast cancer are sometimes stigmatized were significantly more likely to currently be in a support group (χ2= 13.2, p &lt;.01). Caregivers of advanced breast cancer patients were equally as likely as patients to endorse that those with advanced breast cancer have unique, unmet needs.

As the data suggest an association between feeling stigmatized and support group participation, one goal for service delivery would be to implement supportive services which address these unmet needs and perceived biases. The data also suggest that addressing concerns of those caring for advanced breast cancer patients would be beneficial. Taken together, the data strongly support the continued need for educational and support programs to address the needs of those affected by advanced breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-09-09.

Abstract P6-09-10: Informational needs among women considering breast reconstruction post-mastectomy

For many women, the complexity of processing and learning about their breast cancer diagnosis is further complicated by decisions to be made about breast reconstruction post-mastectomy. For women considering reconstruction post-mastectomy, obtaining information about reconstruction procedures and outcomes is a process, and multiple factors may influence the decision-making process. Little is known about the extent to which patient's knowledge and expectations related to breast reconstruction procedures weigh on their decision-making process.

To better understand and meet the needs of women facing reconstruction, the Cancer Support Community surveyed 1,185 women diagnosed with breast cancer. Women answered questions either: online (n = 840) in August, 2010; or via paper and pencil (n = 345) after attending a breast reconstruction workshop held at multiple sites nationwide in 2011. In addition to demographics, and diagnostic and treatment history, women reported their decision regarding reconstruction, experience searching for and receiving information, and expectations about reconstruction.

Respondents were primarily Caucasian (81.9%), and the mean age at diagnosis was 48.9. 21.2% of respondents were first diagnosed with breast cancer in the past year, and 30.0% were diagnosed at least five years ago. Online respondents were more likely to be Caucasian, less likely to have been recently (less than one year) diagnosed with breast cancer, and more likely to have already made a decision regarding reconstruction, as compared to workshop attendees, but were similar in all other respects for these analyses.

Most respondents (57.3%) had either undergone or had decided to undergo breast reconstruction. 18.4% of respondents reported they decided not to undergo reconstruction, and 8.9% reported they were not eligible. Additionally, 15.5% of respondents were currently considering or planning to consider their options for reconstruction at a later time.

Of the women who were currently considering or planning to consider breast reconstruction, information-seeking patterns and informational needs were reported. Aside from their health care team, most women sought additional information about reconstruction from other women with breast cancer (40.9%), medical literature (46.0%), patient support groups (35.6%), friends and family (41.3%), and the Internet (57.2%). Over one-third of respondents considering reconstruction (34.5%) would have liked to have had more information about the risks and benefits of reconstruction at the time of mastectomy versus at a later time. These women also reported a number of factors influencing their current point in the decision-making process, including: concerns about implant safety (83.3%); concerns about additional treatment and recovery (85.5%); concerns about failed procedures (91.5%); and confusion about the reconstruction decision-making process (72.2%).

Survey responses suggest women considering breast reconstruction have a variety of informational needs, some of which are not being met. Results suggest there is still work to be done with regard to establishing realistic expectations about the procedures and outcomes, providing comprehensive information at various stages throughout the process, and across the various choices.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-09-10.

Multiple large enteroliths associated with an incisional hernia: a rare case

The surgeon frequently encounters renal and biliary stones but rarely may also encounter enteric stones or enteroliths. An enterolith is a stony foreign body that is formed in the gastrointestinal tract. We present a rare case of multiple, large enteroliths found associated with a longstanding incarcerated incisional hernia.

Bioresorbable composite screws manufactured via forging process: pull-out, shear, flexural and degradation characteristics

Bioresorbable screws have the potential to overcome some of the complications associated with metallic screws currently in use. Removal of metallic screws after bone has healed is a serious issue which can lead to refracture due to the presence of screw holes. Poly lactic acid (PLA), fully 40 mol% P(2)O(5) containing phosphate unidirectional (P40UD) and a mixture of UD and short chopped strand random fibre mats (P40 70%UD/30%RM) composite screws were prepared via forging composite bars. Water uptake and mass loss for the composite screws manufactured increased significantly to ∼1.25% (P=0.0002) and ∼1.1% (P<0.0001), respectively, after 42 days of immersion in PBS at 37 °C. The initial maximum flexural load for P40 UD/RM and P40 UD composite screws was ∼60% (P=0.0047) and ∼100% (P=0.0037) higher than for the PLA screws (∼190 N), whilst the shear load was slightly higher in comparison to PLA (∼2.2 kN). The initial pull-out strengths for the P40 UD/RM and PLA screws were similar whereas that for P40 UD screws was ∼75% higher (P=0.022). Mechanical properties for the composite screws decreased initially after 3 days of immersion and this reduction was ascribed to the degradation of the fibre/matrix interface. After 3 days interval the mechanical properties (flexural, shear and pull-out) maintained their integrity for the duration of the study (at 42 days). This property retention was attributed to the chemical durability of the fibres used and stability of the matrix properties during the degradation process. It was also deemed necessary to enhance the fibre/matrix interface via use of a coupling agent in order to maintain the initial mechanical properties acquired for the required period of time. Lastly, it is also suggested that the degrading reinforcement fibres may have the potential to buffer any acidic products released from the PLA matrix.

Material characterisation and cytocompatibility assessment of quinternary phosphate glasses

Six phosphate glass formulations (in the system P(2)O(5)-CaO-MgO-Na(2)O-Fe(2)O(3)) were produced with fixed magnesium and calcium content at 24 and 16 mol%, respectively. P(2)O(5) and Fe(2)O(3) were varied between 40-50 and 0-4 mol% respectively, with the balance being Na(2)O. EDX analyses confirmed the final composition of the glasses investigated to within a 1-2 % error margin. Thermal analyses showed a linear increase in T(g) with increasing Fe(2)O(3) and P(2)O(5) contents, with Fe(2)O(3) showing a greater effect than P(2)O(5). This was proposed to be due to the formation of Fe-O-P bonds and an increase in the cross-link density of the glass network enhancing the durability of the glass. The glasses that were investigated revealed a decrease in degradation rate with increasing Fe(2)O(3) and P(2)O(5) contents and again the effect of Fe(2)O(3) was greater. All the above characteristics correlated well with structural changes measured by IR and XPS analyses. Cytocompatibility studies showed good cellular (MG63) response to the glasses up to 168 h in terms of cell viability, proliferation and differentiation. Statistical analysis revealed that all the formulations with the exception of P50Fe4 gave a comparable response to the control (TCP), which suggested that after a threshold level of glass durability is achieved the degradation rate has no or minimal effect on biocompatibility. However, it was seen that the glass chemistry can also affect cellular response, since increasing the P(2)O(5) content promoted phenotypic expression that was not related to degradation rate but to the degradation products. This was supported using an elution assay.

Bioresorbable screws reinforced with phosphate glass fibre: manufacturing and mechanical property characterisation

Use of bioresorbable screws could eliminate disadvantages associated with metals such as removal operations, corrosion, MRI interference and stress shielding. Mechanical properties of bioresorbable polymers alone are insufficient for load bearing applications application as screws. Thus, reinforcement is necessary to try and match or surpass the mechanical properties of cortical bone. Phosphate based glass fibres were used to reinforce polylactic acid (PLA) in order to produce unidirectionally aligned (UD) and unidirectionally plus randomly distributed (UD/RM) composite screws (P40 UD and P40 UD/RM). The maximum flexural and push-out properties for the composite screws (P40 UD and P40 UD/RM) increased by almost 100% in comparison with the PLA screws. While the pull-out strength and stiffness of the headless composite screws were ∼80% (strength) and ∼130% (stiffness) higher than for PLA, those with heads exhibited properties lower than those for PLA alone as a result of failure at the heads. An increase in the maximum shear load and stiffness for the composite screws (∼30% and ∼40%) in comparison to the PLA screws was also seen. Maximum torque for the PLA screws was ∼1000 mN m, while that for the composite screws were slightly lower. The SEM micrographs for P40 UD and P40 UD/RM screws revealed small gaps around the fibres, which were suggested to be due to buckling of the UD fibres during the manufacturing process.

Finite element modelling of the flexural performance of resorbable phosphate glass fibre reinforced PLA composite bone plates

A finite element method is presented to predict the flexural properties of resorbable phosphate glass fibre reinforced PLA composite bone plates. A novel method for meshing discontinuous fibre architectures is presented, which removes many of the limitations imposed by conventional finite element approaches. The model is used to understand the effects of increasing the span-to-thickness ratio for different fibre architectures used for PBG/PLA composites. A span-to-thickness ratio of 16:1 is found to be appropriate for materials with randomly orientated fibres, which agrees well with the test standard. However, for highly aligned materials the model indicates that a span-to-thickness ratio of 80:1 is required, in order to minimise the effects of shear deflection. The model is validated against flexural stiffness data from the literature for a range of polymers, fibres and fibre volume fractions. Generally there is less than 10% error between the FE predictions and experimental values. The model is subsequently used to perform a parametric study to understand what material developments are required to match the properties of PGF/PLA composites to cortical bone. It is concluded that alignment of the fibre is necessary to exceed the 20 GPa target, since the current manufacturing methods limit the fibre length to ∼10 mm, which consequently restricts the flexural modulus to ∼19 GPa (at 50% volume fraction).